Best driving technique for long, steep highway climbs (5–8% gradient)?

[ione]

Hi everyone,

I’ve driven about 1,000 km in my Crosstar so far, and while I’m happy with it overall, there’s one aspect of the car I haven't quite mastered yet.

On my daily commute, I have to drive up a fairly steep section of the highway with a significant incline (averaging 5–6%, with spots reaching 7–8%). I’m not entirely sure what the best way to handle the car is over these 5 kilometers.

To make matters trickier, I usually have to start this climb from a dead stop because there’s a traffic light right at the bottom that I almost always catch on red. If I accelerate gently, the car gets stuck at around 70–80 km/h, but the engine doesn't sound or feel particularly comfortable either. If I try to reach 90–100 km/h to get some momentum and "coast" a bit from there, the engine roars loudly and still struggles to settle down. All of this not using Eco mode.

I’m not sure if this is down to my driving technique or what the most efficient way to drive it would be.

How do you all handle long, steep climbs like this? Any advice or tips would be much appreciated!

Thanks!

[Bristol_Crosstar]

It helps if the battery's near full at the start of the climb, to achieve this you could switch the climate system off then switch it on again at the top of the hill. Also I try and keep the throttle steady rather than putting foot to the floor if possible.

[Downsizer]

What happens if you select a suitable speed in cruise control after setting off and let the car decide for itself?

[Nicksey]

Are you in D or B mode?

I have a few steep hills in the wolds around me, and because they are generally minor roads I drive in B. I haven't had any issues ascending hills.

[jasonevans]

I found a steady throttle application helps rather than flooring the accelerator.

[Sean Regan]

I've a 23reg Crosstar. I drive everywhere in B, sometimes up a steep hill. Never bother about it, I just let the car get on with it. "It knows what it's doing."

[ahavoja]

Climbing a 6% uphill at 100 km/h requires 21 kW of power.
(Calculation: 1300kg * 9.81m/s² * 0.06 * 100km/h / 3.6 = 21kW.)

On top of that the aerodynamic drag at 100km/h requires additional 15kW.
This would mean a total of 21 + 16 = 36kW required. This is already 46% of the maximum 79kW output of the petrol engine of Jazz. This could be why the engine is roaring loudly. Only two solutions come to my mind: driving slower or wearing noise canceling headphones.

When I drove up some mountain roads in Norway, I just tried to enjoy the roaring engine sounds of Jazz. Regardless of the noise, the car dealt quite well with the steep climbs.

[Lord Voltermore]

I agree switching a/c etc off may help as the electric drive can contribute  more before the ICE needs to recharge the HV battery.

Personally I think the mk 4 is  quite good at climbing mountains . Mine climbs Sutton Bank in North Yorkshire UK with ease. (25%  although its  quite short -maybe 2 km.   )  But its easily climbed long alpine passes such as the Transfagarasan  and the Transalpina.

But yes, the ICE can get quite noisy when it has to work hard  on a sustained climb.  Maybe to be expected when climbing a mountain pass  but particularly annoying on a 5% gradient in 'traffic light' country or if such climbs are a large proportion of your kilometers.

Personally  I am willing to tolerate this  temporary extra noise as to some extent you are comparing the contrast with how very quiet the car normally is.  .   Conventional ICE cars with manual transmission can also be noisy when climbing hills ! 

Incidentally some have concerns about regenerative braking when coming down long descents. I find  a combination of D mode, and occasional light use of the brakes if the car starts to build up too much speed works well.  I have never been concerned that the brakes were at any risk of overheating. Indeed I have followed 'conventional' cars down that needed to use their brakes more often than I did.

[NathanC67]

... or if such climbs are a large proportion of your kilometers.

What goes up...

[FMIB]

Personally I use the mash the pedal approach and turn up the music.

[Nicksey]

Incidentally some have concerns about regenerative braking when coming down long descents. I find  a combination of D mode, and occasional light use of the brakes if the car starts to build up too much speed works well.  I have never been concerned that the brakes were at any risk of overheating. Indeed I have followed 'conventional' cars down that needed to use their brakes more often than I did.

Ditto. B most of the time, but on long descents into D.

[ione]

I try not to use the A/C in this case. Probably the car is doing well going up this 5-6 kilometers at 90-100 kms/h but the noise is so disgusting that makes you feel you are making some kind of harm to it.
 Because of that sometimes I prefer to do this sections at 70-80 kms/h but also dont know if you are overheating something or whatever or even make the gas consumption higher, who knows

I΄ll keep experimenting and see where it goes.

Thanks for all the answers!!

[Downsizer]

I think the lower speed will use less fuel because of less air drag, an important factor as ahavoja has pointed out above.